Field of the Invention
The present invention relates to communications control technology.
Description of the Related Art
Augmented reality (AR) technology has been realized in which, in an image of a real environment captured with a digital camera, a mobile phone, or the like, attribute information related to a photographic subject such as a person or an object is displayed combined with the subject. For example, in Japanese Patent Laid-Open No. 2013-242865, technology is described in which, for a captured image, the correspondence of a real space and a virtual space is determined from position information from a GPS (Global Positioning System) or the like, and the virtual space and the captured image are displayed in a superimposed manner.
Also, in Japanese Patent Laid-Open No. 2002-305717, technology is described in which characteristic information related to a photographic subject, such as the face of a person or the outline of an object, is used to identify that subject, and information related to the subject is displayed combined with the subject in the vicinity of the subject in a captured image. Note that Japanese Patent Laid-Open No. 2002-305717 also describes that the camera communicates with a communications apparatus possessed by the subject, and after identifying the subject by that communication, information related to the subject is combined with the subject.
With the technique described in Japanese Patent Laid-Open No. 2002-305717, when communicating with the communications apparatus possessed by the subject, wireless communications by a wireless LAN, Bluetooth (registered trademark), RFID, or the like can be used. Here, in order to communicate by wireless communications with the communications apparatus possessed by the person that is the subject, it is necessary for the communications apparatus to transmit or receive wireless signals. On the other hand, for example in a communications apparatus in which a wireless LAN is adopted, there are cases where, in order to suppress power consumption, switching between a mode in which signals can be transmitted or received, and a mode in which signals cannot be transmitted or received, is performed in a certain cycle. In a case of communicating with this sort of communications apparatus, if information is not requested at least in a period in which a counterpart apparatus can receive a signal, information cannot be obtained from that counterpart apparatus. Therefore, it is important that when communicating with a counterpart apparatus, the communications apparatus is synchronized with a period in which that counterpart apparatus can receive a signal (see Japanese Patent Laid-Open No. 2009-512282).
In a case where several other communications apparatuses are present in the surroundings, it is conceivable to switch between a period in which data can be received and a period in which data cannot be received, in independent cycles for each communications apparatus. In such a case, there is the problem that frequency utilization efficiency can be degraded when the communications apparatus is synchronized individually with each of those other communications apparatuses, and transmits an individual information request for each of those other communications apparatuses.
The present invention provides a technique for improving frequency utilization efficiency when communicating with a plurality of other communications apparatuses that each become capable of data communications in independent cycles.